The effect of charge transport on the photovoltaic properties of dye-sensitized solar cells (DSCs) was investigated by the experimental results and the ion transport. The short current photocurrent density (Jsc) is determined by the electron transport in porous TiO2 when the diffusion limited current (Jdif) due to the I3- transport is larger than the photo-generated electron flux (Jg) estimated from the light harvesting efficiency of dye-sensitized porous TiO2 and the solar spectrum. However, the Jsc value is determined by the ion transport in the electrolyte solution at JdifJg. The J value becomes constant against light intensity, and is expressed as the saturated current (J:C). The JS value depends on the thickness (d) of the TiO2 layer, the initial concentration (COx), and the diffusion coefficient (DOx) of I3-. These suitable parameters were determined by using the ion transport.